We did a boundary survey before putting up our fence. The *line* the neighbors thought was the border was about 3 feet off.We gave neighbors 2 years after the survey to do their own in order to confirm(or not),but no one did so we put up the fence. I would have felt better if they HAD done a survey.I actually thought about hiring someone else to do another survey,but doing one was already costly.
My recommendation is to always do a survey and have the surveyor place markers every 10-20 feet so there is absolutely no question where the property lines are.Then give the neighbor a few months to survey their own property.Many will verbally argue the lines,but will not hire someone(a professional) to disprove them.The person with the current survey by a licensed surveyor will be the one who is in the right.There are ofcourse laws on taking anothers land by simply using it for x amount of years.Each state have different requirements for that(adverse possesion).
Until I put up a fence the neighbor continued to mow the lawn 3 feet into the markers.Mowed around the markers,lol.Essentially continued to use/tend to the land thought to be theirs.Only a fence held them back.
You have the current survey,so it is the neighbors responsibility to have their own done.I still hear my neighbor taking to THIER neighbors about my fence and the *lines*. I waited 2 years to put up my fence.I waited 2 years for them to prove my survey was wrong.I think your neighbor is like mine,and will talk but not spend the money to prove your survey is wrong.All you can do is secure your fencing and ignore.If you can catch the dog call AC. Toss the poo over the line.Lol,the **** is flying now.